Commutator-bar.



F. J. BAIRD.

COMMUTATGR BAR.

APPLICATION FILED OCT. I7. 1914.

' Patented Jan. 11, 1916.

f E h j 7215 @7252 PATENT curios.

FRED J. BAIRID, OF CLEVELAND, OHIO.

' ooMMUTA'mR-BAR.

To all whom 1' t Wia z concern Be it known that I, FRED J. BAIRD, a citi- "zen of the United States, resident of Cleveland, county of Cuyahoga, and State of Ohio, have invented a new and useful Improvement in CommutatorBars, of which the following is'a specification, the principle of the invention being herein explained and 4 the best mode in which I have contemplated of construction of the commutator,

. from which applying that principle, so as to distinguish fit from other inventions.

My invention relates to commutator-bars, its object being to provide a commutatorbar which will be economical of manufacture, which will contribute to the economy and which will be efficient in the performance of its function. I

Said invention consists of means hereinafter fully described and particularly set the closed type and embodying my invention'. Fig. 2 represents an axial section of such commutator. Fig. 3" represents an end elevation of a commutatonbar of the heretofore and commonly used type, and Fig. i

represents a side elevation thereof. Fig. 5 represents an end elevation of a blank bar constructed inaccordance with my invention, are cut,'and Fig. 6 represents a side elevation of a fragmentary portion thereof. Fig. 7 represents an end'elevat-ion of a com-- mutator-ba-r element constructed in accord ance with'my'inventionv and Fig. 8 a side elevation thereof.

The illustrated embodiment of my invention comprises a commutator-bar formed of two elements 1 and 1. Each element consists of a main or bodyportion 2 having the dove-tailbottom 3. Projecting radially with reference to the commutators axis, 'frcm one end .of'the main or body portion is the radial portion 4:. This main or body portion has a lateral face 5 which when the commutator is assembled lies in a plane which contains the commutators axis. as shown in Fig. 1. The opposite face Specification of Letters Patent.

the commutatonbar elements- Patented Jan. 11, 1916.

Application filed October 17, 1914. Serial Ilo. 867,108.

6 lies in a plane which also, when the commutator is assembled, contains .said axis. The one lateral face 7 of the radial portion 4 lies in the same plane with the lateral face 5 of the body portion, as shown in Fig. 7 and the opposite lateral face 8 of said radial portion lies in a plane different from that containing the corresponding lateral face 6, as also shown in said Fig. 7. This face 8, however, is parallel with the face 6 and lies between the plane of face 6 and the plane of faces 5 and 7, as shown.

Each commutator-bar consists of two ele ments such as have just been described, one element, however, being a left and the other a right, that is, they are symmetrical in cross-,sectionsbut have their corresponding faccs reversed. hen these elements are assemoled in the commutator, a left and a right are placed in juxtaposition with the faces 6 in contact, as shown in full and dotted lines in Fig. 7, and when so placed form an outer radial groove or slot 9 parallel with the commutators axis having parallel, side faces. These pairs of elements so placed are assembled to form the complete commutator as shown in Figs. 1 and 2, in which the dove-tail inner. portion of each commutator-bar is held by the rings 10 and 11 joined together by the bolts 12, passing through one of the rings and threaded into the other, as shown. As is customary, s'uitable insulating rings of mica, 13 and 14, are interposed between the commutator-bars and the rings 10 and 11 and suitable insulating strips 15 placed between adjoining commutator-bars, so that the general construction 0f the commutator is identical with that heretofore employed. It will thus be seen that the elements so assembled provide the required radial slots 9 which receive the leads from the armature coils and in which such leads are secured in the u ual manner. In this way a. commutator is constructed in an efficient and economical manner.

in forming the commutator-bar elements just described, I first take a suitable bar of copper and by means of suitable dies draw same into what is known as mill lengths having the .form shown in Figs. 5 and G in which the cross-section is identical in contour with the end elevation of the completed bar, as an inspection of Figs. 5 and 7 will indicate. In drawing this blank bar, however, resort to thedrawin process in which the bar passes througi a suitable my invention,

number of dies which give it the required cross-section and in what at least the last two passes are made while the copper is comparatively cold. This results in what is known as cold or hard-drawn copper. Copper drawn in this manner is of higher conductivity and more uniform in molecular structure than rolled, forged or cast copper. The dies employed are such as to g've the cross-section which is illustrated, such crosssection being' uniform throughout, both as to area and contour. Such section is bounded by a straight line a on one side, two lines 7) and c on the other side, connected at their inner ends by a third line (Z, the outer ends of said two lines 25 and c and the top and bottom of line a being joined by lines 6 and f respectively, as shown in Fig. 5. Line 6, as shown, lies intermediately of the line a and an upward extension of line a. This blank bar is then formed b means of suit able punching dies into the form shown in Figs. 7 and 8, thus forming the complete bar element.

Heretofore it has been customary to first form a mill-length blank bar having the cross-section whose contour is that illus trated by Fig. 3 in which the top and bottom dimensions were those of the complete commutator-bar. From this blank milllength was then punched the-form shown in Fig. 4 after which the commutator-bars were assembled in the hsual manner to form the complete commutator. After this assembling was completed, the commutator was then placed in a milling or slotting machine and the slots 9 milled or out. By constructing the commutator-bar accordin to however, it will be noted that this milling or cutting operation is entirely eliminated as well as all the procedure incident'thereto, all'of which results in a very material economy of operation and in a considerable saving of metal, as will be readily understood by those skilled in the art.

Having fully described my invention, what I claim and desire to secure by Letters Patent is 2- 1.. As a new article of manufacture, a hard-drawn continuous copper bar, having a cross section bounded wholly on one side and partly on the opposite side ing lines, the boundary on the side lastmentioned being completed by the side and bottom contour of part of a straight sided slot, the upper and lower boundaries oiithe cross section being straight lines.

2. As a new article straight bar of hard drawn copper forming a blank from which commutator bar elements may be cut and having a cross-section uniform throughout, both. as to area and by converg,

connected at their of manufacture,r av

contour; said section being bounded on tirely upon one side by a straight line and upon the other side. by two lines and a third line connecting their inner ends, anda top and bottom line connecting the outer ends of said two lines with the said first-named line.

3. As a new article of manufacture, a con1- mutator bar element consisting of a main or body portion having a radial portion integral therewith; said radial portion and the body portion adjacent thereto being bounded by a plane surface on one. side, two plane surfaces on the other side connected at'their inner ends by a third plane surface; and a top and bottom surface connecting the outer extremities of said two plane surfaces and said first-named plane surface.

4. As a new article of manufacture, a commutator bar element consisting of a main or body portion having a radial projecting portion integral therewith, said main or body portion having-two lateral longitudinal faces angularly related to each other, each of which faces constitutes one entire face of said main or body portion, and said radial projecting portion having one of its lateral longitudinal. faces occupying a plane different from either of the planes occupied by the lateral longitudinal faces of the body portion and forming one side of a straight sided slot.

5. A commutator-bar comprising two elements, each element comprising a main or body portion and a radial portion; said main or body portions being in contact with each other and said radial portions forming a longitudinal groove or slot.

6. A commutator-bar comprising two elements, each element consisting of a solid bar of copper comprising a main or body portion and a radial portion; said main or body portions being in contact with each other and said radial portions forming a longitudinal groove or slot.

- 7. As a new'article of manufacture, a com mutator-bar element composed of solid copper and comprising a main or body portion and a radial portion; a cross-section taken upon a plane passing through the radial portion and perpendicular to the axis of the element being entirely bounded by a straight line on one side, two lines on the other side inner ends by a third line; and a top and bottom line connecting the outer ends of said. two lines and said tirstnamed line.

Signed by me, this lstday of O :tober, 19H.

EV M. R. MILLER, D. Fireman. 

